Atmospheric-river-like storm to bring first rain in months to Sonoma County

North Bay residents will experience their first taste of fall storms beginning Sunday night when a strong atmospheric-river-like storm will bring the first bit of rain since early summer.

Areas of Sonoma County farther north, such as Cloverdale and Healdsburg, are expected to receive up to an inch of rainfall, said Dalton Behringer, a meteorologist with the National Weather Service.

Farther south, including Santa Rosa and Petaluma, may expect up to 1/4- to 1/2-inch of rain, he said.

The storm, which is technically an atmospheric river without the tropical moisture, is expected to bring heavy rains and strong winds to the northern West Coast, including Washington, Oregon and Northern California.

For much of the North Bay, though, the storm will bring more mild and pleasant conditions, Behringer said.

The beneficial rains will help purify the air after wildfire smoke funneled into the region, coming from wildfires burning in Northern California and Oregon that brought hazy skies and poor air quality since Tuesday.

“It’s not out of the ordinary, but it is a little stronger than usual, especially in the northern parts of the state,” Behringer said of the incoming storm.

Santa Rosa’s average rainfall for September is 7/100 of an inch.

Starting late Sunday, chances of rain will begin to increase, Behringer said. But the bulk of the rain will come Monday morning to early afternoon.

On Monday night, the storm will start clearing out with some lingering showers Tuesday morning, he said.

The weather service is not concerned about significant wind or flooding for the region, but there could be some localized pooling of water on low parts of roads in northern Sonoma County.

“It’s going to be a pleasant weekend with mild departures and cleaner air,” Behringer said.

Temperatures in the inland North Bay will be in the mid 70s on Saturday and Sunday.

On Monday, it will be slightly cooler in the mid- to upper-60s due to cloud cover. Coastal temperatures will be about 10 degrees cooler than inland temperatures.

You can reach Staff Writer Alana Minkler at 707-526-8531 or alana.minkler@pressdemocrat.com. On Twitter @alana_minkler.